This might be a bug in the official version 2.0 of Raspberry Pi Imager.
Therefore, when writing a custom system image, please configure your username and password, as well as the WiFi network. We recommend that you download and install a version of Raspberry Pi Imager below 2.0 for writing the system.
This is because if you download and install the official Raspberry Pi Imager version 2.0 or higher, you will be unable to configure the WiFi network when writing a custom system image.
Since you are using a Pi 5, you need to install our specified version 2.0.2 Beta of ezblock OS for it to be compatible with the Pi 5.
Please download the 2.0.2 Beta version of the ezblock OS image system using the link below: